Acute airway obstruction associated with the use of bone-morphogenetic protein in cervical spinal fusion

Bone morphogenetic protein (BMP) used in anterior cervical spinal fusion procedures causes an inflammatory response resulting in upper airway obstruction between postoperative days 4-7. The purpose of this study is to determine the incidence and severity of airway complications associated with use of BMP, the associated clinical outcomes, morbidities and mortalities following its use, and to create a clinical awareness of patients with acute airway obstruction associated with the use of BMP in cervical spinal fusion.

This is a retrospective study of 260 patients who underwent cervical spinal fusion procedures with BMP from 2004-2009 and 520 patients, matched on procedure, who underwent cervical spinal fusion procedures without BMP during the same period at a tertiary care center. The two groups were compared on multiple outcome variables: hospital length of stay (LOS), costs, incidence of airway obstruction, unplanned intubations after surgery, tracheotomies, intensive care unit (ICU) admissions, hoarseness, dyspnea, respiratory failure, dysphasia and dysphagia, readmissions, and need for percutaneous endoscopic gastrostomy (PEG) tubes. All outcome variables that were binary in nature were analyzed using linear logistic regression analyses predicting use of BMP. Deaths up to 90 days post surgery were analyzed with a Cox proportional hazards model. Variables significantly related to BMP use were used as covariates in the above analyses.

Patients that underwent cervical procedures with BMP were noted to have significantly longer hospital stays (7.2 ± 11.1 days vs. 4.3 ± 5.2 days, p < 0.001), and greater costs ($129,483 versus $74,974, p < 0.001) than the control group (Table 1). Tracheotomies (Odds Ratio = 3.79, p-value = 0.021), unplanned intubations after surgery (2.81, 0.008), dysphagia (8.94, 0.001), dyspnea (2.43, 0.001), and respiratory failure (3.35, 0.001) were all significantly associated with the BMP group (Table 2 & Figure 1). In addition, hospital readmissions (1.96, 0.040), ICU admissions (3.05, 0.001), and 90 day mortality rates (Hazard Ratio = 2.44, p = 0.047) were significantly worse for the BMP group.

Acute airway obstruction in the postoperative period following cervical spine fusion using BMP is a complication of its use. Due to the degree of obstruction and difficulty with intubation postoperatively, a clinical awareness is necessary to effectively manage these patients. Collaborative efforts between the spine surgeon, anesthesia and the otolaryngologist are required for management of the complications that occur after surgery.